1. Field of the Invention
The present invention relates to an electrical connection structure, a production method thereof, and an electric wiring method. More specifically, the present invention relates to an electrical connection structure using a biopolymer such as DNA, RNA, or a protein, a production method of the electrical connection structure, and an electric wiring method.
2. Description of the Related Art
Heretofore, expectations that biopolymer insulating materials such as DNA, RNA, and proteins would be used as electronic components were low.
However, due to the development of techniques for manufacturing nanometer-scale devices, the uses of such biopolymers as electronic materials for manufacturing electronic devices began to be studied. Further, the use of these biopolymers is also expected in tests and inspections which connect electrodes to the biopolymers to measure their electric properties. The biggest problem in this case is electrical connection between the biopolymers and the electrodes. In a method of producing electrodes that are used in silicon devices and the like, they are generally wired (electrically connected) by forming a pattern on a photoresist with the light exposure method or the electron beam exposure method, and then depositing metals, semiconductors or the like on the pattern. Moreover, there is a method in which a thiol group (SH group) is intentionally added to a molecule, and the molecule having the thiol group added thereto is optionally adhered onto a gold electrode.
However, in methods in which the photoresist is used, the biopolymers, such as DNA, RNA, or a protein, are chemically damaged by an organic solvent or the like used in resist development. Even if the biopolymers are simply adhered onto a metal electrode, electric conductivity varies according to the adhering state of the biopolymers. In the method in which a thiol group is used, materials are limited, and most biopolymers cannot be used.
Further, when a biopolymer such as DNA, RNA, or a protein is simply placed onto a metal (such as gold or platinum) electrode, contact resistance between the metal electrode and the biopolymer is not constant due to the effects of an oxide film on the surface of the metal. Therefore, a stable electrical connection cannot be expected, and the contact resistance value deviates by about 10% or more.
Furthermore, many of the biopolymers such as DNA, RNA, and proteins are insulating materials having a resistance of 5 MΩ·cm or more. When such biopolymers are used as electronic elements, nanometer-scale electrodes need to be formed and disposed so as to be close to the biopolymer. However, since the size of metal wiring is too large (too thick) relative to the size of the biopolymer, it has been difficult to form minute electric wiring.